During the second half of February, the Solar flux has remained at a constant 72, and is likely to remain the same until at least 17th March, which would suggest that we may at last have reached sunspot minimum at the start of Solar Cycle 24.
The A index rose to 12 on February 21st, and dropped back to 5 the next day. The next disturbance will be on Feb 28th, to March 3rd with the index at 15 and the K at 4 followed by another disturbance 8-13th with the A index peaking at 15 on the 8th and 9th. The A index will then rise again to 10 by the 16th for at least 2 days.
In conclusion, the best days for HF reception will be March 4th 5th 14th and 15th with the A index at 5 and the K index at 2, the worst days being the 1st, 8th 9th and 15th.
The National Oceanic and Atmospheric Administration and the US Air Force have predicted the solar flux to remain at 72 from March 1st continuing into April. (From: www.arrl.org)
Maunder Minimum?
It has been suggested that we may be entering another Maunder Minimum, which is the name given to the period roughly from 1645 to 1715, when sunspots became exceedingly rare, as noted by solar observers of the time. It is named after the solar astronomer Edward W. Maunder (1851–1928) who discovered the dearth of sunspots during that period by studying records from those years. During one 30-year period within the Maunder Minimum, for example, astronomers observed only about 50 sunspots, as opposed to a more typical 40,000–50,000 spots. See: http://en.wikipedia.org/wiki/Maunder_minimum
However, Tad Cooke of ARRL, after seeking the opinion of Dr. Kenneth Tapping of the Herzberg Institute of Astrophysics in Penticton, British Columbia recently wrote:
"I think we can relax about any possible upcoming 70-year period of a quiet Sun. We cannot say that it could not happen, but in fact there is nothing unusual about the current Solar Cycle minimum, and really no known method of predicting such a period."
Thanks to Mike Terry and Ken Fletcher for regular updates. Related links can be found at www.jameswelsh.co.nr.
Saturday 23 February 2008
Tuesday 5 February 2008
Propagation February 2008
Propagation Forecast
The second half of January has remained calm with but February will start off disturbed with the A index at 15, and the K at 4. By the 5th Feb, the A will have dropped to 5, and the K to 2, remaining calm until the 9th, when the A index rises to 15 and the K index to 4. By February 14th, conditions will have settled down again, with the A index at 5 and the K at 2, remaining the same until at least the 18th.
The Solar Flux however, is on a downward trend for February, starting off at 80, then dropping to 75 by the 4th and again dropping to 70 by the 14th. In conclusion, HF reception conditions for February should start off disturbed till the 4th, remaining calm till the 8th. The 9th to the 13th will again be disturbed then conditions should remain calm from the 14th. (Based on the 28 day forecast From WM7D.net)
Solar Cycle 23 VS Solar Cycle 24
There is still much debate among the experts about the emergence of Solar Cycle 24. According to this article from ARRL, (http://www.arrl.org/news/stories/2008/01/18/100/) "Old Cycle 23 spots will appear near the Sun's equator. The first spots of Cycle 24 are at a high solar latitude and will have magnetic polarity opposite of the old spots. There was a brief appearance on January 11 by an "almost sunspot" that had disappeared by the following day; it appeared to be a Cycle 24 spot -- with polarity reversed from Cycle 23 spots -- but it was near the equator, which is the wrong place for a new cycle sunspot."
However, looking at the sunspot number chart on http://www.solarcycle24.com/indexdx.htm sunspot numbers have definitely been on a downward trend. April 2006 had the highest sunspot number of 105, compared with April 07 when it was down to 38. It then peaked at 63 in June 07, and has again been on a downward trend remaining at 15 in October and November 07. Then December '07, saw a significant rise to 44.
Propagation Websites.
‘The Basics Of Radio Wave Propagation’ by Edwin C. Jones, MD, PhD (AE4TM) covers the subjects of Aurora, Backscatter and Grey Line propagation and related subjects, plus Maximum User Frequencies etc. The URL is: http://ecjones.org/propag.html. The XE1BEF website has a comprehensive links page of propagation software and specialist websites, although their bulletin is not currently available in English. http://members.fortunecity.com/xe1bef/propagation.htm. Thanks to Mike Terry and Ken Fletcher for links and updates. Links from this article can be found at http://www.jameswelsh.co.nr/
The second half of January has remained calm with but February will start off disturbed with the A index at 15, and the K at 4. By the 5th Feb, the A will have dropped to 5, and the K to 2, remaining calm until the 9th, when the A index rises to 15 and the K index to 4. By February 14th, conditions will have settled down again, with the A index at 5 and the K at 2, remaining the same until at least the 18th.
The Solar Flux however, is on a downward trend for February, starting off at 80, then dropping to 75 by the 4th and again dropping to 70 by the 14th. In conclusion, HF reception conditions for February should start off disturbed till the 4th, remaining calm till the 8th. The 9th to the 13th will again be disturbed then conditions should remain calm from the 14th. (Based on the 28 day forecast From WM7D.net)
Solar Cycle 23 VS Solar Cycle 24
There is still much debate among the experts about the emergence of Solar Cycle 24. According to this article from ARRL, (http://www.arrl.org/news/stories/2008/01/18/100/) "Old Cycle 23 spots will appear near the Sun's equator. The first spots of Cycle 24 are at a high solar latitude and will have magnetic polarity opposite of the old spots. There was a brief appearance on January 11 by an "almost sunspot" that had disappeared by the following day; it appeared to be a Cycle 24 spot -- with polarity reversed from Cycle 23 spots -- but it was near the equator, which is the wrong place for a new cycle sunspot."
However, looking at the sunspot number chart on http://www.solarcycle24.com/indexdx.htm sunspot numbers have definitely been on a downward trend. April 2006 had the highest sunspot number of 105, compared with April 07 when it was down to 38. It then peaked at 63 in June 07, and has again been on a downward trend remaining at 15 in October and November 07. Then December '07, saw a significant rise to 44.
Propagation Websites.
‘The Basics Of Radio Wave Propagation’ by Edwin C. Jones, MD, PhD (AE4TM) covers the subjects of Aurora, Backscatter and Grey Line propagation and related subjects, plus Maximum User Frequencies etc. The URL is: http://ecjones.org/propag.html. The XE1BEF website has a comprehensive links page of propagation software and specialist websites, although their bulletin is not currently available in English. http://members.fortunecity.com/xe1bef/propagation.htm. Thanks to Mike Terry and Ken Fletcher for links and updates. Links from this article can be found at http://www.jameswelsh.co.nr/
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